A facial-recognition system is a data-processing system that employs one or more algorithms for identifying a person from a digital image or video frame. Many facial -recognition algorithms are based on identifying and quantifying distinguishing features of a person's face, such as the relative position, size, and shape of the eyes, the nose, the cheekbones, the jaw, and so forth.
A speaker-recognition system is a data-processing system that employs one or more algorithms for identifying a person from an audio voice sample. Many speaker-recognition systems employ a library of voice prints (also known as templates or models) that are obtained by extracting features from a recording of a person's voice. In such systems, a speaker-recognition algorithm attempts to identify an unknown speaker by determining a best match between an audio sample of his or her voice and a voice print in the library. Speaker-recognition algorithms employ a wide variety of techniques for generating and processing voice prints, including frequency estimation, hidden Markov models, Gaussian mixture models, and decision trees.